Merry Xmas dr j,
You can find instructions for tying the Sailors Coss in a little booklet by the late Brian Field, called "Concearning Crosses".
This little booklet is available through the IGKT Supplies Secretary for the massive price of £2.00,
Lol.
This booklet shows the standard Sailors cross made with two strands doubled to make a four strand French sennit.
The booklet also includes 6 other cross designs.
Well worth owning a copy.
I have seen this pattern somewhere on the net but cannot remember at this time, but I would recoment supporting the IGKT and buying a copy, in fact I would recomend buying a copy of all of the guilds publications, they are all worth having for reference and ideas
I hope this is of help to you.
Take care,
Barry